Microfracture and debridement

J. Richard Steadman, MD, of Vail, U.S.A., presented long-term clinical results with microfracture (MCFR) and debridement for treatment of full-thickness chondral defects. "It's a safe, effective and relatively simple one-stage way to treat Grade IV lesions," Steadman said. significantly improves the functional outcomes and decreases the pain in most patients."

In his study of 235 consecutive MCFR cases with a follow-up of two to 12 years, Steadman evaluated the clinical benefits of the procedure for both isolated and degenerative defects. All outcome variables improved significantly each postoperative year when compared to the preop evaluations.

The greatest improvement, however, was in pain reduction. For example, 75% of the patients experienced an improvement in pain at three years, 19% were unchanged, and for 6%, pain worsened. There was also a 66% improvement in patients' ability to return to strenuous work, a 59% improvement in strenuous sports, and daily living activities improved by 68%. These rates of improvement remained steady without deterioration for up to 10 years.

"We're at eight years now for some, and they continue to have that 75% improvement in pain," Steadman said. "You would think they just stayed the same in pain (improvement), but I think that's still improvement because these people were going in the wrong direction before they had the procedure done."

According to Steadman, the improvement in pain extends into the second year. "Over the first year it improves, so if you find that people aren't getting great pain relief at first, you shouldn't be discouraged. Generally, there's an improvement pattern there," Steadman stated.

In measuring longevity, the Kaplan-Meier survivorship score-which analyzes the need for additional operative treatment of the same lesion-showed 95% and 92% survival at four and seven years, respectively. The revision procedures consisted of repeat microfractures (7), TKR (5) and osteotomy (3).

"I think that no matter how good or bad the cartilage looks when you do a second look," said Steadman, "it's the way it feels to the patient that seems to be the most important. Our second looks did correlate very well with our questionnaires."

For best results, include edges

MCFR, which was developed for treatment of lesions at least 4 mm thick, incorporates some of the principles of drilling, abrasion and chondroplasty. During the procedure, the calcified cartilage layer of the chondral defect is removed with a curette, with attention given to removing the entire layer, including the hard-to-reach edges. A metal pick or surgical awl is used to break through or "fracture" the subchondral bone into the chondral space. Creating approximately three to four perforations per cm2 allows mesenchymal stem cells, marrow and other factors to form a clot, yet maintains bone plate integrity.

Researchers said that success is directly linked to careful fracturing of the edges of the defect, as well as creating an adequate number of cells. "We feel this forms the clot that can regenerate cartilage," Steadman said. "I've actually showed that."

Horse model invaluable

Using a horse model, Steadman worked with William G. Rodkey, DVM, and C.W. McIlwraith, DVM, to perfect some of the MCFR chondral resurfacing concepts, the most important of which is preparation of the bed. "We found that when the layer of calcified cartilage was left, there was hardly any regeneration," Steadman said. "So it went along with the clinical fact that along the edges sometimes didn't heal quite as well. That's because it's harder to get to that spot, so that's where we start using curettes to be sure we get through that layer of cartilage."

Following improved results with the curette technique, Steadman noted, "From my standpoint, it was worth the whole expense of the study, just to have this finding." After performing MCFR for 15 years and recently revising its application, Steadman said he continues to see enhanced results. "The thing we've learned over the past two years is how important it is to do the preparation in the bed before microfracture," he explained.

Steadman's co-authors were J.J. Rodrigo, K.K. Briggs, and William G. Rodkey, DVM.

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